This is an OpenWrt package feed containing community maintained telephony packages.
To use these packages, add the following line to the feeds.conf in the OpenWrt buildroot:
src-git telephony https://github.com/openwrt/telephony.git
This feed should be included and enabled by default in the OpenWrt buildroot. To install all its package definitions, run:
./scripts/feeds update telephony
./scripts/feeds install -a -p telephony
The telephony packages should now appear in menuconfig.